Fire-door draft-check.



No. 796,660- PATENTED AUG. 8, 1905.

E. B. KIRBY. FIRE DOOR DRAFT CHECK.

APPLICATION FILED JUNE 11, 1903.

mnnzw. u. cmwun (.0, FHOYO-LIYHDGRAPNEHS, WASHiNGTGN n c UNITED STATESPATENT OFFICE.

Specification of Letters Patent.

Eatented Aug. 8, 1905.

Appli tion fi1 d June 11, 1903. Serial No. 160,979.

To all whrm it may concern:

Be it known that I, EDMUND B. KIRBY, a citizen of the United States,residing at Rossland, in the Province of British Columbia and Dominionof Canada, have invented a certain new and useful Improvement inFire-Door Draft- Checks, of which the following is a full, clear, andexact description, reference being bad to the accompanying drawings.

Not a few steam-furnaces are provided with mechanism by means of whichthe draft appliances are caused to move toward the open or shut positionin accordance with the variation between predetermined limits of thesteam-pressure in the boiler. The object of such mechanism is toautomatically maintain the steam-pressure between such limits bycontrolling the fire through the draft appliances. It is practicallyimpossible, however, to produce this ultimate result when one employsonly the mechanism commonly employed for this purpose, because wheneverthe fire-doors The present invention relates to mechanismforaccomplishing this purpose which is mainlyuseful in connection withsteam-boilers having the automatic regulating device referred to.

The invention may be here summarized as consisting in the constructionand combination of parts hereinafter described, and pointed outdefinitely in the claims.

In the drawings, Figure l is a front elevation of a furnace equippedwith my invention in an approved form.- Fig. 2 is a plan View of thesame, some of the parts shown in this figure being in section.

Referring to the parts by letters, A represents asteam-furnace of anysuitable construction, and B the escape-flue thereof.

C represents the draft appliance, which in the form shown is a damper ofthe ordinary butterfly variety. It will be understood, of

course, that any other form of damper may be used in place of thatshown.

'D D represent the hinged furnace-doors,

extended finger (Z, which enters a slot 6 in a lever-arm e, which turnsabouta vertical pivot in substantial alinement with the axis of thedoor-hinges. This lever is made fast to the lower end of a rock-shaft E,which is rotatably mounted in a box F, secured to the furnace front, andto the upper end of this shaft a cam is secured. The described mechanismis associated with each door.

Gr represents a horizontal bar supported above the fire-doors in boxesJ, which permit its endwise movement. In the preferred construction thisrod passes through two sleeves H, which are respectively mountedslidably in said boxes, and the sleeves when properly adjusted arerigidly fastened to said bar. The compression-spring M surrounds one ofthese sleeves and thrusts endwise against the adjacent box and a nut 71upon said sleeve, and thus acts to move the bar in one direction as faras it is permitted to move. It is stopped from further movement by ashoulder /b on this sleeve and a loose roller K, lying between saidshoulder and the box J. This loose roller K is for the purpose ofreducing the friction caused by the action of the cam 0 about to bedescribed. Each of these rollers is in engagement with theoperating-face of one of the cams e wherefore when either door is openedthe associated cam acts against the roller, which transmits its pressureto the shoulder h on said sleeve, and thus causes the sleeve H and bar Gto move in opposition to the spring M. Between this bar and the draftappliance there is suitable mechanism which is set in motion by the saidmovement of said bar, whereby embodiment of the invention shown thismechanism is merely a train of bent levers N and connecting-links N,substantially as shown, the last link in the train being connected to anarm C on the projecting spindle C of the damper. It will be understood,however, that any other mechanism adapted to operate the damper and tobe operated or set in operation by the movement of said bar may besubstituted for the specific mechanism shown.

The parts are so connected that when the fire-door is opened the damperwill be closed, and when the fire-door is closed the damper will beopened by the action of the spring to the fullest extent, provided saiddamper is only connected with the mechanism described. In certainconstructions, however, the same and to each of them is attached anupwardly-.

the draft appliance will be closed. In the damper may be alsooperatively connected with an automatic regulating device, such as isreferred to. In that event the opening of the damper may be independentof the reverse movement of bar G.

Having described my invention, 1 claim- 1. The combination of a furnace,its draft appliance and fire door, a longitudinallymovable bar having ashoulder, a rock-shaft suitably mounted and having a cam thereon forengaging said shoulder, an operating-arm rigid upon said rock-shaft, andprovided with a slot, a finger secured to the fire-door and arranged totake in said slot, and mechanism intermediate of said bar and draftappliance, substantially as described.

2. The combination of a furnace, its draft appliance and hingedfire-door, a longitudinally-movable horizontal bar, mechanismintermediate of said bar and the draft appliance, an independentrock-shaft mounted in approximate alinement with the pivotal point ofthe fire-door, an arm rigidly secured to said rock-shaft and providedwith a slot in its free end, a finger carried by the door and arrangedto enter said slot, a shoulder fixed against endwise movement upon saidbar, and a cam 'carried by said rock-shaft and adapted to engage saidshoulder and shift said bar upon the opening of the fire-door.

3. The combination of a furnace, its draft appliance and hingedfire-door, a longitudinally-movable horizontal bar, mechanismintermediate of said bar and the draft appliance, an independentrock-shaft mounted in approximate alinement with the pivotal point ofthe fire-door, an arm rigidly secured to said rock-shaft and providedwith a slot in its free end, a finger carried by the door and arrangedto enter said slot, a shoulder fixed against endwise movement upon saidbar, a cam carried by said rock-shaft and adapted to engage saidshoulder and shift said bar upon the opening of the fire-door, andsprings for retaining said bar in normal position.

4. The combination of a furnace, its'draft appliance, and hingedfire-door, with a longitudinally-movable horizontal bar, mechanismintermediate of said bar and draft appliance, a rock-shaft mounted inapproximate alinement with the door-hinges, a slotted arm secured tosaid rock-shaft, and a finger secured to the door and entering saidslot, a roller upon said bar abutting a shoulder thereon, a cam engagingwith this roller to move the bar in one direction, and a springoperating to move the bar in the opposite direction, substantially asdescribed.

5. In a furnace, the combination with the draft appliance andfire-doors, of a longitudinally-movable bar, mechanism intermediate ofsaid bar and draft appliance, a rock-shaft mounted on the front of thefurnace, an arm secured to said shaft and having aslot in the free endthereof, a pin carried by the door to engage in said slot, a rollerloose upon said bar but held against longitudinal movement in onedirection, and a cam on said rock-shaft and arranged to take against oneof the faces of said roller whereby when the furnace-door is opened,said bar Will be shifted and the draft appliance operated, substantiallyasdescribed.

In testimony whereof I hereunto affix my signature in the presence oftwo Witnesses.

EDMUND B. KIRBY.

Witnesses:

C. V. JENKINS, C. F. LARSEN.

